Free-piston explosive-engine.



Patented Jan. 28, 1902. W. A. SWAN. EBEE PISTON E XPLOS IVE ENGINE.

(Application filed Aug. 31, 1900.)

6 Sheets-Sheet I.

(No Model.)

THE noflms PEYERS c0. PHOTU-LITHQ. WASHINGTON, D A:v

No. 692,2l8. Patentad Jan. 28, I902.

W. A. SWAN. FREE PISTON EXPLOSIVE ENGINE.

(Application filed Aug. 31. 1900.)

6 Sheets-Sheet 2..

(No Model.)

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Patented Ian. 28, I902.

w. A. SWAN. FREE PISTON EXPLUSIVE ENGINE.

(Application filed Aug. 31, 1900.)

6 Sheets-Sheei 3.

(No Modal.)

n4: uoams PETERS 120., wmmnuo" WASHINGTON.

- Patented Jan. 28, I902.

W. A. SWAN. FREE PISTON EXPLOSIVE ENGINE.

(Application filed Aug. 31, 1900.) A

6 Shee ts-Sheet 4.

(No Model.)

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FREE PISTON EX PLOSIVE ENGINE.-

(Apphcat nfll dAug 81 1800) Patented lan. 28, 1902..

6 Sheets-Sheet 5.

um Model.)

N6; 692,2l8. Patented Jam-28, 4902.

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FREE PISTON EXPLOSIVE ENGINE.

(Application filed Aug. 81, 1900.) (Na Model.) 7 6 Sheets-Shoat 6.

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NlTF STATES PATENT OFFICE.

IVILLIS A. SWAN, OF PROVIDENCE, RHODE ISLAND.

FREE-PISTON EXPLOSlVE-ENGINE.

ZZPEGIFIGATION forming part of Letters Patent No. 692,218, dated January28, 1902.

Application filed August 31,1900. Serial No, 28,681. (N0 model.)

To all whom it may concern:

Be it known that I, WILLIS A. SWAN, a citizen of the United States,residing at Providence, in the county of Providence and State of RhodeIsland, have invented certain new and useful Improvements inGas-Engines; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

My invention relates to gaseugines of the type known as free-pistonengines; and it consists principally in providing certain novellyconstructed and arranged valve mechanism for controlling and governingthe speed of the engine and for regulating the supply of oil and air tothe cylinder.

The invention still further consists in pro- 7 viding a simple andeffective means for the return stroke of the piston; and the inventionstill further consists of the general construction, arrangement, andcombination of the various parts, as will be hereinafter more fullydescribed, and particularly pointed out in the claims.

One of the principal objects of the invention is to provide a simple andeffective means for moving the piston on its back stroke with a gradualand uniform movement, so as to rend-er the operation practicallynoiseless.

Another object of the invention is to obtain the greatest of expansiveforce from the expenditure of a minimum quantity of oil.

Still another object of the invention is to provide an independent orauxiliary power and novel mechanism to make the engine selfstarting.

A still further object of the invention is to provide a means forregulating the speed of the engine without the use of speed-changinggear. 7

Other objects, such as dispensing with the usual compensation-gearingused in vehicle propulsion, will become apparent upon furtherdescription of the invention.

These objects are attained by means of the various mechanism illustratedin the accompanying drawings, in which- Figure 1 is a top plan view oftwo gasengines constructed after my improved plan applied to a wheeledvehicle; Fig. 2, a side elevation of the same with the body of thevehicle and a portion of the running-gear removed; Fig. 3, an enlargedtop plan View of one of the gas-engines; Fig. 4, an enlarged sideelevation of the same and air-pump connected thereto; Fig. 5, a verticallongitudinal section of engine and valve mechanism; Fig. 6, a horizontallongitudinal section of the same; Fig. '7, an enlarged top plan of themechanism for controlling the supply of oil and air and for operatingthe reversingclutches; Fig. 8, a front elevation thereof; Fig. 9, ahorizontal section of the reversingclutch mechanism; Fig. 10, a frontelevation of the igniting device detached; Fig. 11, a top plan of thesame, showing the position of the parts in relation to thecylinder-head; Fig. 12, a plan view of the inner face of one of thefly-wheels, showing the clutch-disk seated therein; Fig. 13, a frontelevation of a portion of the front axle and'steering mechanism; Fig.14, a top plan view of the same; Fig. 14, a detail of theoperating-lever and connections, and Fig. 15 a front elevation of one ofthe cylinder-heads with the valve mechanism removed.

As my invention is especially applicable to the propulsion of Wheeledvehicles, although equally well adapted for driving machinery, I haveshown it applied to a four-wheel vehicle, and in order to facilitate itsdescription I will proceed to describe it under the followingheads,viz:first, the supporting-frame and connections; second, the maindriving-shaft; third,- the engine; fourth, mechanism for operating thevalves; fifth, driving and reversing gear; sixth, mechanism foroperating the clutch mechanism and for controlling the supply of oil andair; seventh, steering mechanism, and, eighth the igniting device.

While I show and describe my invention applied to a wheeled vehicle, Ido not seek to claim herein those parts or devices which relate to theparticular mechanism for operatin g the valves, the driving-clutchmechanism, and the sparking igniter, as these will form thesubject-matter of future separate applications.

The supporting-frame and connections. Referring to the several views,the letter a indicates the front axle, b the rear axle, and

c the frame supporting the engines. The

ICO

front of the engine-supporting frame is supported from the front axle bytwo converging bars cl d, suitably braced by bars e e, and its rear bythe arms of two short shafts ff, supported in bearings g g, attached tothe rear axle. The connection between the converging bars and the frontaxle is preferably by means of a ball and socket, although anyWell-known and suitable coupling may be employed. The outer end of eachshaft f carries a gear-wheel, which meshes with an internalgear (notshown, being of the usual form) provided on the inner face of abrake-Wheel is, rigidly secured to the hub of the vehiclewheel. By meansof the mechanism to be hereinafter described motion is imparted to thebrake-wheel to revolve the rear vehiclewheels. Any suitable brakemechanism may be employed. The engine-supporting frame may be of anysuitable or desired construction and is flexibly supported from thefront and rear axles of the vehicle.

The main driving shaft.Journaled in suitable bearing secured upon theside pieces of the engine-supporting frame is the main driving-shaft 2,which has mounted on each end thereof a sleeve 3, carrying asprocketwheel 3, which is connected by a sprocketchain 4 with asprocket-wheel 5 on the shaft f, the purpose of which will behereinafter explained.

The main shaft carries the mechanism for driving the vehicle in aforward direction and for reversing the direction of movement, as willbe hereinafter described.

The angina-In applying my invention to a wheeled vehicle I employ twoengines identical in structure, but independent of each other, so thatthe description of one will apply to the other.

Each engine 6 is supported upon the front and central transverse bars ofthe frame 0. The head 7 of the cylinder or shell is bored transverselyfor the reception of the main shaft and is provided with a longitudinalpassage for the reception of the piston-rod 8. The head 9 of thecylinder is provided with a chamber 10, communicating with a chamber 11of increased diameter. The outer end of the chamber 11 is provided witha screwthreaded plug 12, bored to receive the stem of a valve 13. Thevalve-stem is provided with an enlargement 14, which serves toaccurately guide the valve in its operation. The chamber 10, which mayproperly be termed the oil-chamber, is provided with an oilpassage 15,which is controlled by a needlevalve 16,adjustablein a screw-threadedopening 17 in the aforesaid head. This valve regulates and controls thesupply of oil to the cylinder, the supply being received through a pipe18, leading from asuitable supply-tank 19 to the chamber 10. The head 9is also provided with an air-chamber 20, controlled by a valve 21,provided with air-passages 22.

The valve-stem operates through a plug 23,

screwed into the outer end of the air-chamber, and it is provided withan enlargement 24, which serves to cut off the supply of air and toassist in guiding the movement of the valve. The air-chamber receivesits supply of air from a tank 25, in which the air is compressed bymeans of an air-pump 26 of any suitable type, the pump being run bysprocket wheels and chains driven from the main shaft 2, as shown inFig. 4.

The head 9 is formed with an exhaust-chamber 27, controlled by a valve28, the stem of which works through aplug 29, screwed into the outer endof said chamber. An exhaustpassage 30 leads from the chamber 27 to theopen air. Additional exhaust-ports 30 may be made in the wall of thecylinder ata point just in front of the position of the pistonhead whenthe piston has reached its full outward stroke.

The lower or under side of the piston-rod for a portion of its length isprovided with a rack 31, which meshes with a gear-wheel 32, screwed on asleeve 33, loosely mounted on the main shaft2. The outerend of thesleeve carries a clutch-disk 34, which is provided with right-angleopenings 35 in its outer periphery, and rigidly mounted on the shaft 2is a fly-wheel 36, in the face of which the clutch-disk is looselyseated. In that part of the openings 35 lying parallel with theperiphery of the clutch-disk are placed rollers 37, so that as thefly-wheel is caused to revolve the rollers impinge between the wallofthe flange 38, forming the seat for the clutchdisk, and the wall of saidpart of the openings and cause the clutch-disk to revolve with thefly-wheel during the forward movement of the vehicle. On the reversemovement of the vehicle the clutch-disk will become disengaged from thefly-wheel, as the rollers will fall back to the opposite part of theopenings, which is slightly greater in width than the closed end,springs 33, seated in the inwardlyextending portion of the openings,serving to limit their movement.

In the top central portion of the head 7 is an opening 39, which ispartially closed by a cap 40, bolted between the ribs 41, formed on saidhead. On the under face of the cap 40 is fitted a metal bearing-plate41, vertically adjustable by a screw 42, for guiding the rear end of thepiston-rod in its travel. The ribs 41 extend beyond the rear end of thehead 7 and arejoined together-by a ring 43, internally screw-threaded toreceive an externally-screwthreaded sleeve 44. Secured within thissleeve is one end of a tube 45 of sufficient lengthto accommodate thefull outward stroke of the piston. f

llfecham'smfor operating the valves. J'ournaled in suitable bearings 46,supported from the frame 0, is a shaft 47, which is rotated by anindependent motor 48. This motor may be of any suitable type or style.Rigidly secured on the shaft 47 are two sets of cams, one

set for each engine, and as they are of similar construction it willonly be necessary to describe one set.

The numeral 49 indicates the cam for operating the oil-valve, 50 the camoperating the air-valve, and 51 the cam operating the exhaust-valve. Acam 52, also rigidly secured on the shaft 47, operates avalve-connecting rod 53, which may be suitably supported in anywell-known manner from the cross-bars of the frame a. The rear end ofthe connecting-rod is connected to a valve cam 54, which operates aspring-restrained valve 55 to admit, cut off, and exhaust the air to andfrom the tube 45, said tube being provided with air inlet and outletopenings in its cap 56.

The independent motor is supplied with air under pressure from theair-tank 25 through pipe 57 and branch pipe 58, the latter beingconnected with the three cylinders of the independent motor by pipe 59.Leading in opposite directions from the pipe 58 are two branch pipes 6060, which supply air to each air-chamber of the cylinders of theengines. Thus it will be seen that air is admitted to each air-chamber20 direct from the supplytank 25, the supply of air to theengine-cylinders being regulated by the valves 21 and the valvescontrolled by the earns 50. Also leading from the pipe 58 is a pipe 61,which is provided with branches 62 62, one branch leading to the tube 45of one engine and the other branch leading to the tube 45 of the otherengine.

Driving and reversing gea'iz The sleeve 3 of each sprocket-wheel 3' alsocarries on its inner end an internal gear-wheel 63, which meshes with agear-wheel 64, attached to one end of a short shaft 65, journaled in theprojection of a bearing-block 66, secured on the central cross-bar ofthe frame 0. (See Fig. 11.) Attached to the other end of the shaft 65 isanother gear-wheel 67, which meshes with a gear-wheel 68, loose on theshaft 2. The inner face of the gear-wheel 68 is provided withclutching-teeth 69, which engage similar teeth on the end of a slidableclutch 70, keyed on the main shaft, the other end of said clutch beingprovided with clutching-teeth adapted to engage corresponding teeth onthe inner end of the sleeve 9.

Mechanism for operating the clutch mechanism and for controlling thesupply of oil and atr.-Journaled in bearings 71, mounted on the frontcross-bar, is a rockable shaft 72, provided with wheels 73 73, havingcamgrooves 74 in their outer peripheries. Fulcrumed on an arm 76,projecting from each bearing-block 66, is a lever 77, which has one endbifurcated and secured to the slidable clutch and the other end providedwith a roller 78, operating in the cam-groove 74. Rigidly secured on therockable shaft are two gear-wheels 79 79, which are adapted to mesh withrack-bars 80 80, pivoted to the arms of a fulcrumed lever 81. The lever81 is provided with a spring-actuated pawl 82, arranged to engagefatoothed segment 83 to hold the lever at any desired position. Alsosecured on the rocka ble shaft are cams 84 and 85, which operate thesupply-valves 86 and 87. The cams 84E operate the valves 86 to controlthe supply of oil to the oil-chambers 10, and the cams serve to operatethe valves 87 to control the supply of air to the chamber 20. As theshaft 72 is rocked in one direction the supply of oil and air is turnedon and the clutches moved to engage the gear-wheel 68, and when rockedin the opposite direction the supply of oil and air is cut off and theclutches moved to engage the sleeve 3 to re verse the direction ofmovement of the vehicle. By manipulating the lever 81 a great or smallcharge of oil and air may be supplied to the respective chambers.

Steering WZGClLClTLlSITL-EfiCh end of the front axle is provided with avertical hub 88, in which is journaled the vertical portion of aright-angle arm 89, the horizontal portion of said arm serving as thespindle for the vehicle-wheel. Rigidly secured to the upper end of thevertical portion of each arm 89 is a toothed segment 90, which mesheswith a worm-wheel 91, journaled in a bracket 92, pivoted to the axle.One end of the shaft of each worm-wheel projects through the bracket andis provided with. a sprocket-wheel 93, a sprocket-chain 94 connectingthe two wheels together. Set-screws 95 95 serve to adjust the engagementof the worm-Wheels with the toothed segments and to prevent theiraccidental disengagement.

The numerals 96 96 indicate two air-cylinders having a piston 97 commonto each. The center portion of the piston-rod is provided with a toothedrack 98 and each end with a head 99, one head working in one cylinderand the other head in the other cylinder, as shown in dotted lines inFig. 7. Air under pressure is supplied to the cylinders from theair-supply pipe 57 by means of pipes 100 and ].O1,the two cylindersbeing connected by air-pipe 102. Journaled in a bracket 103 is asprocket-wheel104, adapted to engage to sprocket-chain 91, and agear-wheel 105, adapted to engage the rack 98. Extending upward from thepipe 101 is a tube 106, and within the tube is a rod 107, provided withan operating-lever 108, carrying a pointer. On the upper end of the tubeis a segment 109, provided with degree-marks. Seated in the pipe 101 atits connection with the pipe 100 and with the tube is a three-way valve,which is operated by the rod 107 and lever 108.

By manipulating the lever air from the supply-tank may be turned intoeither cylinder, and as the air rushes in the piston is forced to movethe gear-wheel 105, which being rigid in the shaft with the sprocketwheel 10 1 causes said sprocket wheel to move the sprocket-chain 44 tocut the front vehiclewheels.

In order to obtain a smooth and easy working of the double piston, asmall quantity of glycerin is placed in each cylinder 96.

While I have shown and described a mechanism for steering the vehicle,it is not my intention to claim it herein, as it will be made thesubjectmatter of a future application.

The igniting device-Passing through the head 9 of the cylinder of eachengine is a shaft 109, carrying on its inner enda contact-point 110 andprovided on its outer end with an arm 111. A spring 112 bears againstthe arm 111 and serves to maintain the contact-point in normal contactwith a toothed sparker 113, secured on the inner end of a shaft 114,

, which passes through each head 9 and has secured on its outer end afour-arm ratchetwheel 115. On the outside of each head 9 is a rockablesleeve 116, which carries at one end a pawl 117, adapted to engage thearms of the ratchet-wheel, and at its other end an arm 116, adapted tobe engaged by a cam 118, secured on the shaft 47. The sleeve extendsoutwardly from the cylinder-head and is attached to the said head bymeans of a screw-rod passing through it, a spring serving to keep thearm in constant contact with the face of the cam. The shaft 109 is.properly insulated from the cylinder-head and is connected with onepole of a battery 119, the other pole of the battery being in electricalconnection with the sparker. Each device is operated by its particularcam, which causes, as the cam-shaft rotates, the pawl of the fulcrumedsleeve 116 to move the ratchet one step and' the sparke'r to move foursteps or points, so that four successive sparks are rapidly made,thereby positively insuring an explosion of the explosive mixture ineach engine-cylinder.

An engine constructed upon the plan of my invention will prove economicin the consumption of oil and will work silently, smoothly, andregularly.

It will be noticed that the means (air-pressure) for returning thepiston on its back stroke is positive in its character and that thepiston is returned with the same positiveness Whatever may be itsposition, whether at rest at half or any part of its working stroke.

The operation of the engine is as follows: The oil and air tanks havingreceived their necessary supply and it is desired to start the machine,the controlling-lever 81 is operated to cause the cams to open the oiland air valves to admit oil and air into their respective chambers, andthence to the cylinder. The air being under pressure, the oil isatomized as it enters the cylinder. \Vhen the required supply of oil andair has entered the cylinder, the explosion takes place, the igniter-cambeing so arranged that it will cause the igniting device to act at theproper time. The explosion of the mixture will force the piston on itsWorking or outward stroke, im-

parting motion to the driving-shaft through the medium of the pistongear-wheel 32, which causes the clutch-disk to engage the fly-wheel.When the piston has reached the limit of its stroke, it will be returnedby the force of the air rushing into the tube 45, the air being admittedby the valve 55, which has been opened by the cam 52 operating theconnecting-rod 53 audits cam 54:. At the same time the piston is beingforced back by the pressure of the air the cam 51 causes theexhaust-valve to open and permit the remaining portion of the expandedgas to escape through the exhaustpassage 30, a portion having alreadyescaped through the ports 30. As soon as the piston is returned thecycle is repeated. Of course it will be understood that in the presentinstance the engines perform the work alternatelythat is to say, whilethe piston of one engine is making its working stroke the piston of theother engine is on its return stroke, the cams of one engine beingdifferently positioned to those of the other engine.

When the engine is at rest and it is desired to start the machine, theadmission of air into the cylinders will set the engine in motion, thusgiving it an initial starting before the explosion takes place. This isaccomplished by means of the cams 50, which are set on the independentor auxiliary motor-shaft 47 in such manner that the air-valves areoperated slightly in advance of the oil-valves. This is an importantfeature of my invention, as it enables me to do away with the usualcrank starting device.

Having thus fully described myinvention, What I claim, and desire tosecure by Letters Patent, is

1. In a gas-engine,the combination of a cylinder, a piston, mechanismssupplying air and oil to said cylinder, the air being under pressure,whereby an initial movement maybe given to the piston by the pressure ofsaid air before the explosion, mechanism supplying the air, underpressure, to return the piston, and an independent motor operating theair and oil supplying mechanisms.

2. In a gas-engine, the combination of a cylinder, a piston, valvessupplying air and oil to the explosion end of the cylinder, the airbeing under pressure, whereby an initial movement may be given to thepiston by the pressure of said air before the explosion, a valvesupplying air, under pressure, to return the piston, an air supply underpressure, mechanism operating the several valves, and an independentmotor operating the valve mechanism.

3. In a gas-engine, the combination of a cylinder, a piston, valvessupplying air and oil to the explosion end of the cylinder, a valvesupplying air to return the piston, an independent shaft carrying cams,adapted to operate the several valves, an air-supply under pressure, andan independent motor operating said shaft, whereby the cams are causedto alternately open the valves to admit air and oil to the explosion endof the cylinder and to return the piston.

4. In a gas-engine, the combination with the cylinder and pistonthereof, of a shaft operated independently of the motive power of theengine, an air-valve, a cam on said shaft for operating said valves tosupply air to the engine-cylinder, and means for supplying air to therear end of the piston to return it on its back stroke.

5. In a free-piston gas-engine, the combination with the cylinder andpiston thereof, of an air-supply reservoir, an air-chamber inclosing therear end of the piston, and means for alternately supplying air to thefront of the piston and to the rear of the same.

6. In a free-piston gas-engine, the combination with the cylinder andpiston thereof, of an air-supply reservoir, and auxiliary shaft, amotive power, independent of the enginedriving power, for driving saidshaft, and means for alternately supplying air to the front end of thepiston and to the rear end thereof.

7. Inafree-piston gas-engine,1he combination with the cylinder andpiston thereof, of an air-chamber, independent of the enginecylinder,receiving the rear end of the piston, said chamber being provided withair inlet and exhaust ports, a valve arranged to alternately open andclose said ports,an air-supply reservoir, and means for alternatelysupplying air to the front and rear ends of said piston.

8. In afree-piston gas-engine, the combination with the cylinder,air-supply valve and piston thereof, of an air-chamber, independent ofthe engine-cylinc'ler, receiving the rear end of the piston, saidchamber being provided with air inlet and exhaust ports, a shaftcarrying cams, and an independent motor for operating said shaft wherebysaid cams are alternately operated to supply air to the front and rearends of the piston.

9. In a free-piston engine, the combination with the cylinder and pistonthereof, ofan airchamber receiving the rear end of the piston, saidchamber being provided with an air-inlet and an exhaust-port, a valvearranged to open and close both the air inlet and the exhaust port, andmeans for operating the valve.

10. In a free-piston engine, the combination with the cylinder andpiston thereof, of an airchaniber receiving the rear end of the piston,said chamber being provided with an air-inlet and an exhaust-port, avalve arranged to open and close both the air-inlet and theexhaust-port, a cam arranged to operate the valve, a rod connected tothe cam, and a rotatable cam arranged to operate the rod and thereby thevalve-cam and valve.

11. In a free-piston gas-engine, the combination with the main cylinderand piston thereof, said piston provided with a rack, of an independentair tube or cylinder receiving the free end of said piston, adriving-shaft mesh with the piston-rack, and a motor, in-

dependentof the main motive power, for causing a supply of air to enterbehind the piston to give the engine its initial movement and supplyingair to the tube or cylinder to positively return said piston on its backstroke, whereby motion is imparted to the drivingshaft.

13. In a free-piston gasengine, the combination with the main cylinderand piston thereof, said piston being provided with a rack, of anindependent air tube or cylinder receiving the free end of the piston,said air-. tube being provided with air-inlets and exhaust-ports, avalve arranged to alternately open and close said ports, and a motor,independent of the main motive power, for causing a supply of air toenter the air-tube to force the piston on its return stroke.

14. In a gas-engine, the combination with the oil and air supply valvesand means for operating the valves to force the oil and air into theengine-cylinder, of a free-acting piston, an air tube or cylinderreceiving the free end of the piston, said air-tube being provided withair-inlets and exhaust-ports, a valve arranged to alternately open andclose said ports, and a motor, independent of themain motive power tocause air to be supplied to the air-tube to force said piston on itsback stroke.

15. In a gas-engine, the combination with the oil and air supply valves,and a shaft provided with means for operating the valves to force theoil and airinto the engine-cylinder, of a free'acting piston having itsfree end operating in an independent tube or cylinder, air inlet andexhaust valves in said tube, and a motor independent of the main motivepower, for driving the shaft, whereby air and oil are supplied to themain or engine cylinder and air to the independent cylinder to force thepiston on its return stroke.

16. In a gas-engine, the combination with the oil and air valves, and ashaft provided with means for operating the valves to force the oil andair into the engine-cylinder, of a free-acting piston, an independentair tube or cylinder receiving the free end of the piston, said air-tubebeing provided with air inlet and exhaust ports, a valve arranged toalternately open and close said ports, means for operating said valve,and a motor, independent of the main motive power, for driving theshaft,whereby air and oil are supplied to the main or engine cylinderand air to the independent cylinder to force the piston on its returnstroke.'

17. In a gas-engine, the combination with the oil and air valves, and ashaft provided with means for operating the valves to force oil and airinto the engine-cylinder, of a freeactingpis'ton, said piston beingprovided with a rack, an independent air tube or cylinder receivingthefree end of the piston, a drivlug-shaft carrying a gear-wheel adaptedto mesh,with the piston-rack, and a motor, independent of the mainmotive power, for operating the valve-operating shaft to supply air andoil to the engine and air to the tube or cylinder to retn rn said pistonon its back stroke.

18. In a gas-engine, the combination with the oil and air valves, and ashaft provided with means for operating the valves to force oil andairinto the engine-cylinder, of a freeacting piston, said piston beingprovided with a rack, an" independent air tube or cylinder receiving thefree end of the piston, said airtube being provided with air inlet andexhaust ports, a valve arraiiged to alternately open and close saidports, a driving-shaft carrying a gear-wheel adapted to mesh with thepinion-rack, and a motor, independent of the main motive power, fordriving the valveoperating shaft, whereby air and oil are supplied tothe engine and air to the tube or cylinder to return said piston on itsback stroke. In testimony whereof I affix my signature in the presenceof two Witnesses.

, WILLIS A. SWAN. Witnesses:

GUY E. PADGETT, J. R. NOTTINGHAM.

